Why is mass treated differently from charge in relativity?

[peeyush_ali]

Mass and charge are qualities of any substance found in nature. That's because they can produce fields of forces. Fields have the capability to do work so we say that energy is stored in fields.but why mass alone is a condensed form of energy as E=MC^2 suggests..why not E=qC^2 ? I mean charge and mass are similar (except for dissimilarities like charges repel and also attract and produce magnetic fields when accelerated) even charge is relativistic invariant but where as mass is relativistic variant..why is this so??
" bending space produces mass " is that true? if yes then why not charge?? or is there something besides space which on bending causes charge?? why are the laws partial with mass but not charge..

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I have not started learning any of the relativity principles..I just know that all of them are derived based on this simple fact derived by Maxwell that for a given medium the velocity of light is constant = 1/(u0 e0)^1/2...and that is irrespective of any relative motion of an observer
an observer traveling with any velocity will observe the speed of light to be constant for that medium..and from this we can derive any law of length or anything...but i don't understand how mass can be changed??
mass is a conserved quantity like charge..hm..can anyone suggest me about all this??

 

[member 141513]

hello peeyush_ali,
i've just finished reading your post.
i think u should first know that in relativity,mass is also an invariant, it is because, by choosing different reference frame to describe the mass,we should get the same natural phenonmenon.
The reason why we need to "alter" the value of mass is to make the concept of relativity easier to be accepted.
Einstein had said in his paper that actually, the relativitistic mass has no meaning.
Because the existence of mass is also an invariant event in space-time.
the calculation of relativistic mass is to compare what the other reference frame measured using its ruler and clock so that other natural laws such as momentum conservation laws,energy conservation laws can be described in the same format.